.nav {
    height: 1.706667rem;
    border-bottom: 1px solid #b2b2b2;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 99;
    background-color: #fff;
}

.nav .title {
    font-size: 0.453333rem;
    color: #2f2f2f;
    text-align: center;
    line-height: 1.946667rem;
}
.nav .back-icon {
    width: 0.72rem;
    height: 0.72rem;
    position: absolute;
    top: 0.613333rem;
    left: 0.32rem;
    background-image: url('./img/back.png');
    background-size: cover;;
}